President Barack Obama says nobody disputes that chemical weapons were used in Syria. He says that use violates international law and poses, in his words, a "danger to our security."

Obama says the world saw thousands of videos, cellphone pictures and social media posts about the damage inflicted by the chemical weapons attack outside Damascus last month that the U.S. says killed more than 1,400 people. He said military strikes on Syria would make Syrian and U.S. children alike safer in the long run.

But Obama conceded it is impossible for the United States to right every wrong and that the country cannot be the world's policemen.

"We cannot resolve someone else's civil war through force," Obama said, but added the United States could protect Syrian children.

The president says the U.S. knows that Syrian President Bashar Assad's regime was responsible. He says Assad's forces prepared the attack in the days beforehand. He says they distributed gas masks to their personnel, then fired rockets into neighborhoods the regime was trying to rid of opposition forces.

Obama on Tuesday used a televised address to the nation to explain his thinking on the ongoing fighting in Syria. He said the use of chemical weapons on Aug. 21 shifted his thinking and that the United States must respond with a military strike to deter future use of such weapons.

The president says he long resisted calls for military action in Syria because he didn't think force could solve the Syrian civil war. But he says he changed his mind after Syria's government gassed its own citizens.

He also pledged that he won't deploy ground combat troops or wage a prolonged air campaign against Syria. Obama also promised he would not pursue an open-ended military action.

Obama said he realized that many Americans were weary of military action after the wars in Iraq and Afghanistan. He said the limitations he was imposing on the potential strike would ensure against the U.S. sliding down a slippery slope into another prolonged war.

The president said it was within the U.S.' ability to prevent Assad from using chemical weapons again by launching military strikes. Obama also said other nations' leaders would see the consequences of using such weapons and think twice.

Obama says he's working closely with world leaders.

He says he's continuing discussions with Russian President Vladimir Putin, while dispatching Secretary of State John Kerry to meet with his Russian counterpart on Thursday. Obama also says he's speaking with leaders of France and Britain and will work with Russia and China to put forward a resolution at the United Nations Security Council requiring Assad to give up his chemical weapons.

Obama made his remarks as U.S. officials explore whether a Russian proposal to put Syria's chemical weapons under international control might work, and as the administration seeks congressional support for an attack.

Congressman Andre Carson (D-Indiana) says he is still contemplating how he will vote on a request by the Obama administration for Congress to authorize military force against Syria.

"For the last several weeks, my constituents have voiced their concern about proposals for military strikes in Syria. I share these concerns. I am pleased to see President Obama's willingness to explore every diplomatic option before resorting to military action," Carson said in a statement Tuesday night. "Every military action deserves serious deliberation. I will continue to pursue details about the risks and costs of a strike. However, diplomacy must remain our primary tool. If we can negotiate the transfer and destruction of all Bashar al-Assad's chemical weapons, the international community should come together to pursue this approach."

Congresswoman Susan Brooks (R-Indiana) said earlier Tuesday she has decided she will not vote in favor of the administration's request.

"Even after two classified briefings with Administration officials and today's Committee on Homeland Security hearing on the issue, I simply feel the White House has failed to outline a specific plan for action and success in the context of our national interest," Brooks said.

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